Cheese is prepared from milk that has been clotted, such as by the addition of an acid, inoculum, or rennet to form a curd. Whey (Senim lactis) is a cloudy liquid, the watery part of milk and is separated from the curd in the process of making cheese by centrifugation, decanting, or filtration. The most important ingredients of whey include lactose (and slight amounts of glucose and galactose), protein (albumin, and globulin), vitamin B (mainly riboflavin), and minerals and trace elements. Whey also has a milk-fat (triglyceride) content which can be either removed by centrifugation, or incorporated by homogenization. Whey is used as a valuable food supplement, but its shelf life is relatively short, therefore it has to be refrigerated and it has to be consumed rather quickly. Two major types of whey are available as protein sources, acid whey with a pH of &lt;5.1 which is obtained from cottage cheese manufacture, and sweet whey with a pH of &gt;5.6, resulting from the rennet-coagulated cheese manufacture. The composition of both of these whey varieties is slightly different, and variable, both of these varieties contain from about 0.7% to about 0.8% protein on a liquid basis, with whey proteins representing from about 10% to about 12% of the total whey solids.
Small quantities of condensed, deproteinated whey are used for making milk vinegar by fermentation with lactonitril. In the '50s there was a suggestion that the high vitamin content of whey would make it a suitable cosmetic ingredient, but in spite of that and its high nutritional value, liquid whey is generally considered to be a waste product and is mainly discarded due to its unattractive appearance, undesirable flavor and poor shelf life. Some cosmetic products have been made with small concentrations (max, up to about 20%) of liquid whey, their shelf life was unsatisfactory at higher whey solids concentrations.
Dry whey is a processed, usually freeze dried or spray dried powder which corresponds to about 15.4 times the weight of liquid whey. Some forms of whey powder are processed into concentrated protein isolates also being known under various trade names such as lactoferrin. These dry whey concentrates are generally used as an antimicrobial protein and an immuno-modulator, and usually contain over 25% protein. When the non-proteinaceous, low molecular weight constituents such as lactose, minerals, non-protein nitrogen and vitamins are removed, usually by physical separation (e.g. ultrafiltration, precipitation or dialysis), whey protein concentrates of over 90% protein can be obtained in the retentate. The high-protein concentrates are usually employed after pH adjustment in producing lactose, alcohol, single-cell protein, yeast, galactose, glucose, cattle feed and various pharmaceuticals. Except for the reduced moisture content, unprocessed dry whey usually retains the same constituents in the same proportion as in the fresh sweet or fresh acid whey from which it is dehydrated.
There have been proposed liquid beverages in the prior art based on whey, flavored, or otherwise, but in spite of their obvious low cost and high nutritional value they have achieved only limited acceptance. The problem has been mainly due to the fact that these beverages require refrigeration and also have a limited shelf life. Similarly, cosmetic products with a relatively low whey content were proposed, but they did not become commercially viable due to their limited shelf life mainly, because even with a low whey content their shelf life could not be extended by the use of conventional preservatives.
U.S. Pat. No. 3,922,375 discloses a pH-adjusted aqueous protein isolate solution prepared by mechanical separation from whey which can be incorporates into beverages and used as a clouding agent.
U.S. Pat. No. 4,086,367 describes a fruit-flavored, shelf stable and self-preserving, low-liquid content alimentary composition prepared from fruit flavors, finely dispersed fat particles enrobed in a fat enrobing agent that prevents coalescing of the fat particles by preventing fat-to-fat contact, wherein the enrobing agent is dried yeast or whey.
U.S. Pat. No. 4,615,900 discloses a method for producing an acidic dry-powdered beverage mix of a co-dried, pH adjusted protein or protein hydrolyzate-emulsifier complex.
U.S. Pat. No. 4,746,527 relates to a powder composition of fats, lactic proteins including whey, and lactose and other carbohydrates with gaseous cavities, that can be reconstructed to form a frothy beverage.
U.S. Pat. No. 4,790,998 relates to a clouding or creaming agent for acid-type beverages, from whey proteins and a lipid system.
U.S. Pat. No. 5,153,019 relates to a rice bran-honey beverage containing a whey protein concentrate.
U.S. Pat. No. 5,478,587 discloses a low-fat, substantially cholesterol and lactose-free, flavored dry dessert product containing whey protein or concentrates thereof.
French Pat. No. 2,665,056 discloses a drink for human or animal consumption from cow's or goat's milk with or without a flavorant.
German published patent application No. 2,535,904 relates to a beverage of fruit juice, whey, milk protein as a nutrient solution for lactic acid and yoghurt bacteria cultures, lactic acid from a highly cultured lactic acid bacteria culture, and other yoghurt bacteria cultures, with lactose as a sweetener, prepared by heating to 48.degree. C. for optimal bacterium formation, and then heated to 85.degree. C., and homogenized.
German published patent application No. 3,034,038 discloses a method for preparing a beverage formed by mixing whey with concentrated fruit juice, and then dispersing and homogenizing the mixture.
Soviet patent No. 805,987 discloses a soft drying from defatted milk that is filtered and flavored.
Soviet patent No. 1,829,902 relates to a whey-based beverage prepared by mixing it with a fruit juice and sugar syrup, and pasteurizing and clarifying by proteolytic fermentation, then filtration and deactivation of the ferment.